mirror of
https://gitlab.winehq.org/wine/wine-gecko.git
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149 lines
3.8 KiB
C++
149 lines
3.8 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
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*/
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this file,
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* You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef js_heap_api_h___
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#define js_heap_api_h___
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/* These values are private to the JS engine. */
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namespace js {
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namespace gc {
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/*
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* Page size must be static to support our arena pointer optimizations, so we
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* are forced to support each platform with non-4096 pages as a special case.
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* Note: The freelist supports a maximum arena shift of 15.
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* Note: Do not use JS_CPU_SPARC here, this header is used outside JS.
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*/
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#if (defined(SOLARIS) || defined(__FreeBSD__)) && \
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(defined(__sparc) || defined(__sparcv9) || defined(__ia64))
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const size_t PageShift = 13;
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const size_t ArenaShift = PageShift;
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#elif defined(__powerpc64__)
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const size_t PageShift = 16;
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const size_t ArenaShift = 12;
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#else
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const size_t PageShift = 12;
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const size_t ArenaShift = PageShift;
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#endif
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const size_t PageSize = size_t(1) << PageShift;
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const size_t ArenaSize = size_t(1) << ArenaShift;
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const size_t ArenaMask = ArenaSize - 1;
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const size_t ChunkShift = 20;
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const size_t ChunkSize = size_t(1) << ChunkShift;
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const size_t ChunkMask = ChunkSize - 1;
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const size_t CellShift = 3;
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const size_t CellSize = size_t(1) << CellShift;
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const size_t CellMask = CellSize - 1;
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/* These are magic constants derived from actual offsets in gc/Heap.h. */
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const size_t ChunkMarkBitmapOffset = 1032368;
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const size_t ChunkMarkBitmapBits = 129024;
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/*
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* Live objects are marked black. How many other additional colors are available
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* depends on the size of the GCThing. Objects marked gray are eligible for
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* cycle collection.
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*/
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static const uint32_t BLACK = 0;
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static const uint32_t GRAY = 1;
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} /* namespace gc */
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} /* namespace js */
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namespace JS {
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struct Zone;
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} /* namespace JS */
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namespace JS {
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namespace shadow {
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struct ArenaHeader
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{
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js::Zone *zone;
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};
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struct Zone
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{
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bool needsBarrier_;
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Zone() : needsBarrier_(false) {}
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};
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} /* namespace shadow */
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} /* namespace JS */
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namespace js {
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namespace gc {
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static JS_ALWAYS_INLINE uintptr_t *
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GetGCThingMarkBitmap(const void *thing)
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{
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uintptr_t addr = uintptr_t(thing);
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addr &= ~js::gc::ChunkMask;
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addr |= js::gc::ChunkMarkBitmapOffset;
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return reinterpret_cast<uintptr_t *>(addr);
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}
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static JS_ALWAYS_INLINE void
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GetGCThingMarkWordAndMask(const void *thing, uint32_t color,
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uintptr_t **wordp, uintptr_t *maskp)
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{
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uintptr_t addr = uintptr_t(thing);
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size_t bit = (addr & js::gc::ChunkMask) / js::gc::CellSize + color;
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JS_ASSERT(bit < js::gc::ChunkMarkBitmapBits);
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uintptr_t *bitmap = GetGCThingMarkBitmap(thing);
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*maskp = uintptr_t(1) << (bit % JS_BITS_PER_WORD);
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*wordp = &bitmap[bit / JS_BITS_PER_WORD];
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}
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static JS_ALWAYS_INLINE JS::shadow::ArenaHeader *
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GetGCThingArena(void *thing)
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{
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uintptr_t addr = uintptr_t(thing);
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addr &= ~js::gc::ArenaMask;
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return reinterpret_cast<JS::shadow::ArenaHeader *>(addr);
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}
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} /* namespace gc */
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} /* namespace js */
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namespace JS {
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static JS_ALWAYS_INLINE Zone *
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GetGCThingZone(void *thing)
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{
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JS_ASSERT(thing);
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return js::gc::GetGCThingArena(thing)->zone;
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}
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static JS_ALWAYS_INLINE Zone *
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GetObjectZone(JSObject *obj)
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{
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return GetGCThingZone(obj);
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}
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static JS_ALWAYS_INLINE bool
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GCThingIsMarkedGray(void *thing)
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{
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uintptr_t *word, mask;
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js::gc::GetGCThingMarkWordAndMask(thing, js::gc::GRAY, &word, &mask);
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return *word & mask;
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}
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static JS_ALWAYS_INLINE bool
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IsIncrementalBarrierNeededOnGCThing(void *thing, JSGCTraceKind kind)
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{
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js::Zone *zone = GetGCThingZone(thing);
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return reinterpret_cast<shadow::Zone *>(zone)->needsBarrier_;
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}
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} /* namespace JS */
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#endif /* js_heap_api_h___ */
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